1. Field of the Invention
The present invention relates to a heat exchanger which is preferably used for a heater core or the like for an automotive air conditioning device, and more particularly relative to a tank and a base plate connected to the tank.
2. Description of Related Art
Conventionally, inventors of the present invention have proposed a heat exchanger, as disclosed in JP-A-8-226786 (EP 0718580 A1), to manufacture the heat exchanger in a low cost and to reduce the number of assembling steps. The heat exchanger includes a tank 1 and base plate 2 as shown in FIG. 10. In the heat exchanger, unfolded metal plates are respectively folded and the folded portions are connected to each other to form the tank 1 and the base plate 2. However, in the heat exchanger, connection surfaces are formed at folded portions of the tank 1 to ensure a connection area to be brazed. When the base plate 2 is connected to an opened end portion of the tank 1, a clearance 51 is formed in an connection potion A as shown in FIG. 11. Further, a claw portion 3 for receiving an insert plate for holding a core portion of the heat exchanger is provided on a folded portion of the base plate 2 in lateral direction (i.e., a short side portion) as shown in FIG. 10. Since a brazing material is clad on the core portion before brazing, the insert plate may extend outwardly in a longitudinal direction of the base plate so that the claw portion 3 may extend outwardly in the longitudinal direction of the base plate. Therefore, the folded portion of the base plate in the lateral direction also extends outwardly in the longitudinal direction of the base plate 2 so that the clearance 51 shown in FIG. 11 is further enlarged. Thus, the tank 1 and the base plate 2 cannot be securely connected and brazed to each other.